The invention relates to a chip card with a semiconductor chip, in which for the energizing of the chip and for the bidirectional data transmission by means of a terminal from and to the chip, first transmission means are provided, such as contacts and/or second transmission means, such as contact-free coils and/or capacitors, and/or other energy- and data-transmission means, there being provided on the chip a drivable function element.
With use of chip cards for the bidirectional data transmission it is required in many cases always to hold only one transmission path for data and/or energy in an active function and to cut off the other transmission paths from their connection to the outside. For example, a chip card which is active per contact connection should ensure that the contact-free connections to the outer world are cut off.
Through DE 39 35 364 as well as U.S. Pat. No. 5,206,495 its U.S. equivalent a chip card has become known which is capable of automatically determining its mode of functioning either over contacts or coils. For this the chip card contains a chip (part 2) in which the usual parts of a microcomputer, such as a computing mechanism and a storage element, are accommodated. To the chip there is connected on the one side a contact field with contacts according to ISO standard 7816. On the other side coils are connected to the chip, which serve for the transmission of energy and the bidirectional data flow. In the chip an electronic element is present, which makes possible the automatic switchover from coil function to contact function and conversely, so that the chip card, either contact-free or contact-encumbered, is capable of exchanging energy and data with writing/reading terminals. The chip part 2 consists of two essential function elements, namely a part 2.1xe2x80x94which performs in correspondence to the writing/reading terminal which brings about the switchover between contact field and coilsxe2x80x94and a part 2.2 in which the remaining chip functions such as computing mechanism and storage response unit are located. In this part there are carried out those processes which are of importance for the user of such a chip card, such as debiting of amounts of money, storage of identification numbers, etc. These two parts 2.1 and 2.2 are connected with each other by means of lines A1, A2, A3 . . . which serve in the chip for the part 2.2 as input and output lines for the processing of the information in the computing mechanism of that part 2.2.
Through EP 534 559 A1 there has been proposed a chip card according to ISO standard 7816 and to provisional ISO standard 10536, which, contact-free or contact-encumbered, can exchange energy and data with writing/reading terminals. The data can be read out according to two different modes, either over long distance by means of low energyxe2x80x94in which case only a part of the integrated switching circuit is activated (energy sparing mode)xe2x80x94or there takes place an exchange of energy and data according to the standardized mode by means of the contacts. As further relevant publications there have become known: DE 43 10 334, PCT/IB 96/00518, DE 195 372, as well as DE 195 31 275.
An analysis of the possibilities of separating chip parts and a solution of the problems is to be derived from DE 197 52 695 xe2x80x9cElectronic switching element for the blocking of electronic parts in a chip card.xe2x80x9d
Through DE-C-44 03 753 a combined chip card has become known which operates both contact-free and also contact-encumbered, the IC of which is embedded into a contact block which presents an additional protection and can be used as a sensitive switching element for electronic purposes. In particular, through the function as switching element, the electronic system can be switched on or off by a card user for purposes of remote transmission. Furthermore, the contact block can be exchanged.
Through DE-A-197 23 272 a chip card with a microcomputer unit has become known, which is connected with electrically conducting contact surfaces for the contact-encumbered data transfer, and which has a data storage component which is connected with an antenna for contactless data transfer. A control unit in dependence on a control level establishes a connection between an antenna and storage element or an antenna and microcomputer unit.
Underlying the invention is the problem of securely carrying out the electrical separation of connections of the chip card to the outer world, in dependence on a functional or operating mode of the card.
The chip card of the aforementioned category according to the invention consists in that:
1. the function element in dependence on a first or second function or on a first or second working mode of the semiconductor chip drives one of two switching elements (S1 or S2),
2. wherein the first function or working mode of the semiconductor chip is characterized by an energy and/or data exchange over the first transmission means,
3. wherein the second function or working mode is characterized by an energy and/or data exchange over the second transmission means,
4. wherein the first function is active, as it cuts off parts of, or the entire electrical connection of the data and/or energy exchange to maintain the second function of the card over the further transmission means, with the exception of the active function, and conversely.
According to the invention it is a matter of a chip card with a chip in which different drivable components, such as microprocessors and storage elements are contained. The most diverse means can serve for the energizing, and for bidirectional data transmission from and to the chip. There are possible and known contacts, as well as means for the contactless data transmission, in the form of coils or capacitors. There can also be provided other energy and data transmission means and/or means such as are present as electronic, miniaturized elements for the reception of sound or pressure or for the capacitive reception of electric signals in fingerprint sensors. On the chip there is provided a drivable function element which recognizes the particular functional state or mode, whether the chip card is to operate contact-encumbered or contactless. This function element can be a comparison member, for example a comparator or operation amplifier, according to the part 2.1.2 of DE-C-39 35 364.
The function element, in dependence on this first or second function or operating mode of the chip, triggers one of the switching elements S1 or S2. With the elements S1, S2 it is a matter of electronic parts or switching circuits which are suited for cutting off electric line connections, insofar as they have a voltage lying on their control input. The first function/mode of the semiconductor chip is characterized by an energy exchange and/or data exchange with the outside of the card (with parts that are not contained in the chip, such as, for example terminals) over the first means. The first means are those that mark the active state of the card. In a card this can be the connection over the contacts or over the coils. The second function/mode is characterized by an energy and/or data exchange over further means. If the first function is active, then parts of, or the entire electrical connection of the data and/or energy exchange should be cut off from the further or other functions of the card with the exception of the active function. The particular active function should cut off the possible other functions from any data exchange.
The function mode is to be described in the example of a chip card that contains both contacts and also coils for the energy and/or data exchange with the environment, as with a terminal. If data come in over the contacts, these data are worked up for further use in a part, as an entry port for transport over lines. The data arriving from the coils are worked up by a further part, as entry port, for transport over further lines. If now the function element perceives the activation of the chip card over the contacts or the coil, as, for example, the origin of the voltage, for example according to DE-C-39 35 364, then one of the switching elements S1 and S2 can be activated and the connection to outside the card can be cut off. In such manner, for example, the modulated-on signals that arrive over the coils, can be cut off before their demodulation, for the purpose of data recovery from the entry port, part 2.1.4.
It can happen that certain functions are activated within the same brief spans of time. In each case the dominant function which arises first in time over the time span, should block the others over the switching elements S1, S2.
In all cases in which other functions are already active, the function should serve the switching elements S1 or S2 over dominant contacts. Therewith a clear priority is to be established between the different possible active states.
If a card is activated over contacts or if it is activated during another function over contacts, the contacts represent the strongest energy supply (power supply). Also, the reference potential (VCC of the contacts) is stable with respect, for example, to contact-free reference potential, since it is connected with the potential in a terminal. If line connections or signal outputs or data lines from or to the further function parts are laid on the voltage base potential of the contact input, it is ensured that no other signalxe2x80x94namely no other data, signals, logical levels or energiesxe2x80x94remain stable; they will adapt themselves to the reference potential. In this manner there is determined an electrical dominance of the contact function.